Marine transmission actuation system

Abstract

An actuator for a marine transmission uses four cavities of preselected size in order to provide four potential forces resulting from pressurized hydraulic fluid within those cavities. The effective areas of surfaces acted upon by the hydraulic pressure are selected in order to provide increased force to move the actuator toward a neutral position from either a forward or reverse gear position. Also, the relative magnitudes of these effective areas are also selected to provide a quicker movement into gear than out of gear, given a similar differential magnitude of pressures within the cavities.

1. A marine transmission actuation system, comprising:
 a housing structure; 
 an actuator movably supported within said housing structure; 
 first, second, third, and fourth cavities disposed at least partially between said actuator and said housing structure; 
 a first surface of said actuator having a first effective area which is responsive to pressure within said first cavity to exert a first force against said actuator in a first direction; 
 a second surface of said actuator having a second effective area which is responsive to pressure within said second cavity to exert a second force against said actuator in a second direction; 
 a third surface of said actuator having a third effective area which is responsive to pressure within said third cavity to exert a third force against said actuator in said first direction; and 
 a fourth surface of said actuator having a fourth effective area which is responsive to pressure within said fourth cavity to exert a fourth force against said actuator in said second direction, said fourth effective area being larger than said first effective area. 
 
   
   
     2. The marine transmission actuation system of  claim 1 , wherein:
 said third effective area is larger than said second effective area. 
 
   
   
     3. The marine transmission actuation system of  claim 1 , wherein:
 said first and third surfaces are movable relative to each other. 
 
   
   
     4. The marine transmission actuation system of  claim 3 , wherein:
 said second and fourth surfaces are movable relative to each other. 
 
   
   
     5. The marine transmission actuation system of  claim 1 , wherein:
 said actuator is slidably supported by said housing structure for movement along an axis. 
 
   
   
     6. The marine transmission actuation system of  claim 5 , wherein:
 said actuator comprises a piston member, a first ring defining said third surface and a second ring defining said fourth surface; and 
 said first and second rings being movable relative to said piston member in a direction parallel to said axis. 
 
   
   
     7. The marine transmission actuation system of  claim 1 , wherein:
 said actuator is movable into forward, neutral and reverse gear positions relative to said housing structure. 
 
   
   
     8. The marine transmission actuation system of  claim 7 , wherein:
 said neutral gear position is between said forward and reverse gear positions. 
 
   
   
     9. The marine transmission actuation system of  claim 8 , wherein:
 said actuator is movable in said first direction from said reverse gear position to said neutral gear position and is movable in said first direction from said neutral gear position to said forward gear position. 
 
   
   
     10. The marine transmission actuation system of  claim 8 , wherein:
 said actuator is movable in said second direction from said forward gear position to said neutral gear position and is movable in said second direction from said neutral gear position to said reverse gear position. 
 
   
   
     11. A marine transmission actuation system, comprising:
 a housing structure; 
 an actuator movably supported within said housing structure; 
 first, second, third, and fourth cavities disposed at least partially between said actuator and said housing structure; 
 a first surface of said actuator having a first effective area which is responsive to hydraulic pressure within said first cavity to exert a first force against said actuator in a first direction; 
 a second surface of said actuator having a second effective area which is responsive to hydraulic pressure within said second cavity to exert a second force against said actuator in a second direction; 
 a third surface of said actuator having a third effective area which is responsive to hydraulic pressure within said third cavity to exert a third force against said actuator in said first direction, said first and third surfaces being movable relative to each other; and 
 a fourth surface of said actuator having a fourth effective area which is responsive to hydraulic pressure within said fourth cavity to exert a fourth force against said actuator in said second direction, said fourth effective area being larger than said first effective area, said actuator being slidably supported by said housing structure for movement along an axis, said actuator being movable into forward, neutral and reverse gear positions relative to said housing structure. 
 
   
   
     12. The marine transmission actuation system of  claim 11 , wherein:
 said third effective area is larger than said second effective area; and 
 said second and fourth surfaces are movable relative to each other. 
 
   
   
     13. The marine transmission actuation system of  claim 11 , wherein:
 said actuator comprises a piston member, a first ring defining said third surface and a second ring defining said fourth surface; and 
 said first and second rings being movable relative to said piston member in a direction parallel to said axis. 
 
   
   
     14. The marine transmission actuation system of  claim 11 , wherein:
 said neutral gear position is between said forward and reverse gear positions. 
 
   
   
     15. The marine transmission actuation system of  claim 14 , wherein:
 said actuator is movable in said first direction from said reverse gear position to said neutral gear position and is movable in said first direction from said neutral gear position to said forward gear position. 
 
   
   
     16. The marine transmission actuation system of  claim 14 , wherein:
 said actuator is movable in said second direction from said forward gear position to said neutral gear position and is movable in said second direction from said neutral gear position to said reverse gear position. 
 
   
   
     17. A marine transmission actuation system, comprising:
 a housing structure; 
 an actuator movably supported within said housing structure; 
 first, second, third, and fourth cavities disposed at least partially between said actuator and said housing structure; 
 a first surface of said actuator having a first effective area which is responsive to hydraulic pressure within said first cavity to exert a first force against said actuator in a first direction; 
 a second surface of said actuator having a second effective area which is responsive to hydraulic pressure within said second cavity to exert a second force against said actuator in a second direction; 
 a third surface of said actuator having a third effective area which is responsive to hydraulic pressure within said third cavity to exert a third force against said actuator in said first direction; and 
 a fourth surface of said actuator having a fourth effective area which is responsive to hydraulic pressure within said fourth cavity to exert a fourth force against said actuator in said second direction, said fourth effective area being larger than said first effective area, said actuator being movable into forward, neutral and reverse gear positions relative to said housing structure, said neutral gear position being between said forward and reverse gear positions, said actuator being movable in said first direction from said reverse gear position to said neutral gear position and said actuator being movable in said first direction from said neutral gear position to said forward gear position, said actuator being movable in said second direction from said forward gear position to said neutral gear position and is movable in said second direction from said neutral gear position to said reverse gear position. 
 
   
   
     18. The marine transmission actuation system of  claim 17 , wherein:
 said third effective area is larger than said second effective area; 
 said first and third surfaces are movable relative to each other; and 
 said second and fourth surfaces are movable relative to each other. 
 
   
   
     19. The marine transmission actuation system of  claim 18 , wherein:
 said actuator is slidably supported by said housing structure for movement along an axis. 
 
   
   
     20. The marine transmission actuation system of  claim 19 , wherein:
 said actuator comprises a piston member, a first ring defining said third surface and a second ring defining said fourth surface; and 
 said first and second rings being movable relative to said piston member in a direction parallel to said axis.